same here, my two mocha showed signs so they went straight to QT, using copper treatment keeping copper between 1.5 and 2, change at least 1-2 gallons of water every day to keep ammonia down(only have about 6 gallons in a 10gallon tank for the qt so 1-2 gallons is a decent water change) They spots dissapeared after a few days but will be leaving them in QT for the full recommended term. Try to feed both the QT and DT with the NLS thera A or the ocean nutrition formula two which both have garlic and other helpful additives in it.
The firefish I got from the same store is perfectly fine.
And Im in the same boat with feedings, work 8 hours a day so I can drop a few pellets in the morning but not again till 5:30 or so...